 Hello, my name is Sarah Wuznowski. I am a medical physics therapy resident at Buffett Cancer Center at the University of Nebraska Medical Center And today I'll be presenting my research titled using flattening filter free beams and electronic tissue compensation whole breast irradiation With deep inspiration breath holds for left-sided breast cancer or more simply Breathe in and hold it reducing the strain of deep inspiration breath holds in whole breast irradiation Taken a deep breath and hold it now imagine you are diagnosed with breast cancer You're about to begin your first radiation therapy treatment Your heart is racing Then you're instructed to hold your breath Patients with left-sided breast cancers undergoing radiation therapy this deep inspiration breath hold technique allows us to reduce the dose to their heart Which reduces possible cardiac toxicities? By this point in my presentation I'm sure most of you are about ready to give up and we're only halfway through a typical treatment time As you can see this technique puts strain on our patients This led my team and I to ask the question. What can we do to ease that burden without sacrificing plan quality? To explain how we attempted to do this. We need to take a step back and cover some basics In radiation therapy we are tasked with treating the cancer and sparing the healthy tissue All this sounds simple It's actually quite challenging and requires an entire team of physicists planners therapists and physicians to ensure we reach our goal Each patient receives a treatment plan specific to them and their anatomy Which is then delivered by a linear accelerator or a linac that generates in the case of breast cancer Ionizing radiation in the form of photons that destroy that cancer The linac is built with modifiers that help us shape our outgoing radiation beam One of those modifiers is a flattening filter which acts exactly as you'd expect it flattens our beam Traditionally, this is favorable to deliver a homogenous dose to a large target in the most efficient manner Imagine I ask you to draw a straight line be pretty helpful if I gave you a straight ruler, right? That flattening filter is our straight ruler However, that filter also absorbs some of our outgoing photons making for an efficient delivery when time is of the essence So we asked to speed up the delivery of the treatment plan. Can we use a flattening filter free beam to achieve an equivalent plan? We discovered that using a planning technique called electronic tissue compensation We can manually edit a map of where photons will deposit the dose and Use a flattening filter free beam to deliver a plan that is equivalent to if not better than the one using the flatten beam Now you may be asking equivalent by what standards? One of physicians reviewing a plan that have various dose symmetric endpoints or dose goals for both the target and the normal tissues Using those dose symmetric endpoints, we can compare plans side by side to see which one covers more of the target and spares more than normal tissues When the plan using the flatten beam is compared to the flattening filter free plan They were statistically and clinically identical for all endpoints except one The flattening filter free plan was even better at sparing the right breast It also reduced the delivery time by 20 to 42 percent These results will hopefully encourage the field of radiation oncology to adopt this novel method of using a flattening filter free beam And electronic tissue compensation to deliver whole breast radiation for left-sided breast cancers and reduce the strain of the deep Inspiration breath holds on our patients making their treatments as easy as breathing. Thank you